The research described involves the characterization of the L-arabinose binding protein of Escherichia coli (and several related proteins) to establish molecular parameters required for their function as intermediaries between the cell and its environment. Such studies involve (a) completion of the primary amino acid sequence analysis of native arabinose binding protein and subsequent consideration of its structure, (b) a comparison of the sequences of selected portions of native ABP, mutant ABP, galactose binding protein and related proteins (described herein) to establish common structures reflecting their mutual involvement in transport functions, (c) isolation and characterization of mutants affecting the regulation of binding protein synthesis, and (d) considering restoration of function to transport defective mutants by reconstitution of the binding protein transport function. Additional information on the interactions of binding proteins and membranes will be pursued by attempting to locate a binding protein like system in a wall-less prokaryotic organism (e.g., mycoplasma). In such systems, binding proteins are expected to have adapted by forming stronger associations with the cell membrane.